1. Field of the Invention
This invention relates to the field of refurbishing of non-stick polymer-coated bake ware and cookware products.
2. Background Art
In the field of commercial cookware and bakeware, many products employ non-stick and other release-enhancing coatings (including silicone-based glaze, rubberized silicones, and flourocarbon polymer coatings such as PTFE""s, PFA""s, and FEP""s). After such commercial cookware and bakeware products have been repeatedly used and consequently experience wear, it is desirable to be able to remove such coatings from the products so that a new coating of the fluorocarbon polymer (or other similar silicone-based or polymer coating) can be applied to refurbish old product. This process is desirable so that:
1. production rejects can be reworked, thereby reducing scrap, and
2. pans can be recoated, extending the life of the pans.
The second purpose has significant economic and financial implications within the baking industry.
A suitable technology would have to be effective, economical, safe, environmentally friendly and commercially viable. Prior art processes, including grit blasting, shot peening, high temperature oven burning and molten salt bath immersion did not meet the criteria needed to ake xe2x80x9cstrippingxe2x80x9da viable process.
The process of the instant invention solves the problem of removing coatings using water cutting technology.
In order to remove the old coating water pressure exceeding 35 KPSI and a special swivel multi-port, high speed rotating cleaning head are utilized. This head had to be made to exacting dimensions so that when rotating it would properly sweep and strip the coating from the recessed areas of bakeware or cookware products employing water jets that are angled to correspond with the primary angles of the surfaces of the cookware or bakeware product to be cleaned. Proper use of such a cleaning head enables a cookware or bakeware product to be cleaned in a single pass.
The first generation of cleaning heads that may be used with the present invention includes a configuration utilizing four sapphire orifices or jewels. Two of the orifices are 0.008 inches and should be angled at 21xc2x0 and 25xc2x0. The other tow orifices are 0.005 inches angled at 21xc2x0 and 25xc2x0. The head is stainless steel and must rotate at a minimum of 500 rpm. It is driven by compressed air.
The preferred head configuration, as described in more detail with reference to FIG. 2, includes seven nozzle positions, each of which may be plugged or fitted with a removable nozzle head. Each removable nozzle head may have an orifice sized between 0.0001 and 0.25 inches in diameter. The head is stainless steel and rotates at approximately 1600 rpm. It is driven by compressed air.
Selection of process variables are key to the present invention. Key process variables (is additional to head design) include: head standoff, tracking, speed and tracking overlap.
Each bakeware or cookware product has unique removal requirements. Process variables must be changed so that the proper level of removal can be efficiently achieved.